#ifndef _PGM_H_
#define _PGM_H_
 
#include <math.h>
#include <string.h>
 
#define PGM_MAGIC "P5"
 
#ifdef _WIN32
#define STRTOK_R(ptr, del, saveptr) strtok_s(ptr, del, saveptr)
#else
#define STRTOK_R(ptr, del, saveptr) strtok_r(ptr, del, saveptr)
#endif
 
typedef struct _pgm_t {
    int width;
    int height;
    unsigned char *buf;
} pgm_t;
 
int readPGM(pgm_t* pgm, const char* filename)
{
    char *token, *pc, *saveptr;
    char *buf;
    size_t bufsize;
    char del[] = " \t\n";
    unsigned char *dot;
 
    long begin, end;
    int filesize;
    int i, w, h, luma, pixs;
 
 
    FILE* fp;
    if ((fp = fopen(filename, "rb"))==NULL) {
        fprintf(stderr, "Failed to open file\n");
        return -1;
    }
 
    fseek(fp, 0, SEEK_SET);
    begin = ftell(fp);
    fseek(fp, 0, SEEK_END);
    end = ftell(fp);
    filesize = (int)(end - begin);
 
    buf = (char*)malloc(filesize * sizeof(char));
    fseek(fp, 0, SEEK_SET);
    bufsize = fread(buf, filesize * sizeof(char), 1, fp);
 
    fclose(fp);
 
    token = (char *)STRTOK_R(buf, del, &saveptr);
    if (strncmp(token, PGM_MAGIC, 2) != 0) {
        return -1;
    }
 
    token = (char *)STRTOK_R(NULL, del, &saveptr);
    if (token[0] == '#' ) {
        token = (char *)STRTOK_R(NULL, "\n", &saveptr);
        token = (char *)STRTOK_R(NULL, del, &saveptr);
    }
 
    w = strtoul(token, &pc, 10);
    token = (char *)STRTOK_R(NULL, del, &saveptr);
    h = strtoul(token, &pc, 10);
    token = (char *)STRTOK_R(NULL, del, &saveptr);
    luma = strtoul(token, &pc, 10);
 
    token = pc + 1;
    pixs = w * h;
 
    pgm->buf = (unsigned char *)malloc(pixs * sizeof(unsigned char));
 
    dot = pgm->buf;
 
    for (i=0; i< pixs; i++, dot++) {
        *dot = *token++;
    }
 
    pgm->width = w;
    pgm->height = h;
 
    return 0;
}
 
int writePGM(pgm_t* pgm, const char* filename)
{
    int i, w, h, pixs;
    FILE* fp;
    unsigned char* dot;
 
    w = pgm->width;
    h = pgm->height;
    pixs = w * h;
 
    if ((fp = fopen(filename, "wb+")) ==NULL) {
        fprintf(stderr, "Failed to open file\n");
        return -1;
    }
 
    fprintf (fp, "%s\n%d %d\n255\n", PGM_MAGIC, w, h);
 
    dot = pgm->buf;
 
    for (i=0; i<pixs; i++, dot++) {
        putc((unsigned char)*dot, fp);
    }
 
    fclose(fp);
 
    return 0;
}
 
int normalizeD2PGM(pgm_t* pgm, double* x)
{
    int i, j, w, h;
 
    w = pgm->width;
    h = pgm->height;
 
    pgm->buf = (unsigned char*)malloc(w * h * sizeof(unsigned char));
 
    double min = 0;
    double max = 0;
    for (i=0; i < h; i++) {
        for (j=0; j < w; j++) {
            if (max < x[i*w+j])
                max = x[i*w+j];
            if (min > x[i*w+j])
                min = x[i*w+j];
        }
    }
 
    for (i=0; i < h; i++) {
        for (j=0; j < w; j++) {
            if((max-min)!=0)
                pgm->buf[i*w+j] = (unsigned char)(255*(x[i*w+j]-min)/(max-min));
            else
                pgm->buf[i*w+j]= 0;
        }
    }
 
    return 0;
}
 
int normalizeF2PGM(pgm_t* pgm, float* x)
{
    int i, j, w, h;
 
    w = pgm->width;
    h = pgm->height;
 
    pgm->buf = (unsigned char*)malloc(w * h * sizeof(unsigned char));
 
    float min = 0;
    float max = 0;
    for (i=0; i < h; i++) {
        for (j=0; j < w; j++) {
            if (max < x[i*w+j])
                max = x[i*w+j];
            if (min > x[i*w+j])
                min = x[i*w+j];
        }
    }
 
    for (i=0; i < h; i++) {
        for (j=0; j < w; j++) {
            if((max-min)!=0)
                pgm->buf[i*w+j] = (unsigned char)(255*(x[i*w+j]-min)/(max-min));
            else
                pgm->buf[i*w+j]= 0;
        }
    }
 
    return 0;
}
 
int destroyPGM(pgm_t* pgm)
{
    if (pgm->buf) {
        free(pgm->buf);
    }
 
    return 0;
}
 
#endif /* _PGM_H_ */